The mechanism of fluid transport by epithelial tissues such as kidney cells has been investigated by fluorescence microscopy of living cultured renal cells using methods developed in this laboratory. These studies have produced a detailed understanding of the mechanism of fluid transport. Recently, we have shown that charged sugar moieties of the glycocalyx on the epithelial cell surface play an important role in the controlling the near-membrane pH and microenvironment. - fluid transport, kidney, MDCK cells, glycocalyx